:root{
  --bg:#F4EDE1;--bg-top:#F9F4EB;--bg-bottom:#EFE6D7;--panel:#FFFCF6;--panel-2:#EDE3D2;--border:#E0D3BE;
  --accent:#1D6A96;--accent-dark:#124C6E;--ochre:#6E2E1B;--text:#2A2219;--muted:#6E6152;--success:#2F8A5B;--warn:#B9740F;--error:#B23A2C;--white:#FFFFFF;
  --globe-1:#E3EEF4;--globe-2:#C9DCE8;--clear:transparent;
  --grid-line:rgba(42,34,25,.04);--ink-a06:rgba(42,34,25,.06);--ink-a10:rgba(42,34,25,.10);--veil:rgba(42,34,25,.32);
  --border-soft:rgba(224,211,190,.85);--hi-edge:rgba(255,255,255,.92);--white-a22:rgba(255,255,255,.22);
  --accent-a06:rgba(29,106,150,.06);--accent-a08:rgba(29,106,150,.08);--accent-a10:rgba(29,106,150,.10);--accent-a12:rgba(29,106,150,.12);--accent-a25:rgba(29,106,150,.25);--accent-a45:rgba(29,106,150,.45);
  --ochre-a16:rgba(110,46,27,.16);--success-a20:rgba(47,138,91,.20);
  --flag-red:#C4363C;--flag-navy:#2F3C6E;--flag-white:#FFFFFF;--flag-black:#1F1A15;--flag-gold:#E2A92B;
  --font-display:'Inter','Noto Sans SC','PingFang SC','Hiragino Sans','Apple SD Gothic Neo','Malgun Gothic','Microsoft YaHei',system-ui,sans-serif;
  --font-body:'Inter','Noto Sans SC','PingFang SC','Hiragino Sans','Apple SD Gothic Neo','Malgun Gothic','Microsoft YaHei',system-ui,-apple-system,'Segoe UI',sans-serif;
  --font-mono:'JetBrains Mono',ui-monospace,'SFMono-Regular',Menlo,Consolas,'Liberation Mono',monospace;
  --weight-normal:400;--weight-display:500;--weight-strong:600;
  --r-focus:6px;--r-panel:14px;--r-lg:12px;--r-card:10px;--r-pill:999px;--r-round:50%;
  --shadow-card:0 1px 2px var(--ink-a06),0 14px 40px var(--accent-a10);
  --shadow-chip:0 1px 2px var(--ink-a06),0 8px 22px var(--accent-a10);
  --gutter:32px;--page-width:1360px;--reading-width:820px;--header-height:72px;--anchor-offset:144px;
  --size-body:16px;--size-small:14px;--size-tiny:12px;--size-h1:clamp(52px,4.45vw,66px);--size-h2:clamp(28px,3vw,42px);--size-h3:22px;
  --tracking-display:-.025em;--tracking-cjk:-.02em;--tracking-mono:.12em;
  --ease:ease;--duration:.2s;--reveal-duration:.35s;
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{background:var(--bg);scroll-padding-top:88px;scroll-behavior:smooth}
html.nav-open{overflow:hidden}
body{
  font-family:var(--font-body);font-size:var(--size-body);line-height:1.6;color:var(--text);background-color:var(--bg);
  background-image:linear-gradient(var(--grid-line) 1px,var(--clear) 1px),linear-gradient(90deg,var(--grid-line) 1px,var(--clear) 1px),linear-gradient(180deg,var(--bg-top) 0,var(--bg) 560px,var(--bg-bottom) 900px,var(--bg) 1400px);
  background-size:48px 48px,48px 48px,100% 100%;background-repeat:repeat,repeat,no-repeat;
  overflow-x:clip;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;
}
[hidden]{display:none!important}
img{max-width:100%;height:auto;display:block}
svg{flex-shrink:0}
a{color:var(--accent);text-underline-offset:.2em}
button,input,select,textarea{font:inherit}
button{cursor:pointer}
button:disabled,.btn[aria-disabled="true"]{cursor:not-allowed;opacity:.55}
button{color:inherit}
ul{list-style:none}
h1,h2,h3{font-family:var(--font-display);font-weight:var(--weight-display);overflow-wrap:break-word;text-wrap:balance}
h1{font-size:var(--size-h1);line-height:1.12;letter-spacing:var(--tracking-display)}
h2{font-size:var(--size-h2);line-height:1.25;letter-spacing:var(--tracking-cjk)}
h3{font-size:var(--size-h3);line-height:1.4}
:lang(zh-CN) h1,:lang(zh-TW) h1,:lang(ja) h1,:lang(ko) h1{letter-spacing:var(--tracking-cjk)}
:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:var(--r-focus)}
::selection{background:var(--accent-a25);color:var(--text)}
.no-break{white-space:nowrap}
.sprite{position:absolute;width:0;height:0;overflow:hidden}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}
.wrap{width:100%;max-width:var(--page-width);margin-inline:auto;padding-inline:var(--gutter)}
.reading-wrap{width:100%;max-width:var(--reading-width);margin-inline:auto;padding-inline:var(--gutter)}
.sec{padding-top:80px;padding-bottom:80px}
.grid{display:grid;gap:24px}
.grid>*{min-width:0}
.grid-three{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid-five{grid-template-columns:repeat(5,minmax(0,1fr))}
.stack>*+*{margin-top:24px}
.section-head{margin-bottom:32px;max-width:820px}
.section-head p{margin-top:16px;color:var(--muted)}
.kicker{font-family:var(--font-mono);font-size:var(--size-tiny);letter-spacing:var(--tracking-mono);text-transform:uppercase;color:var(--ochre);margin-bottom:16px}
.muted{color:var(--muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.card,.panel{background:var(--panel);border:1px solid var(--border-soft);box-shadow:inset 0 1px 0 var(--hi-edge),var(--shadow-card);border-radius:var(--r-card);padding:28px;min-width:0}
.panel{border-radius:var(--r-panel)}
.prose{min-width:0;overflow-wrap:break-word}
.prose p,.prose ul,.prose ol,.prose pre,.prose blockquote,.prose table{margin-block:20px}
.prose h2{margin-block:48px 20px}
.prose h3{margin-block:32px 16px}
.prose ul,.prose ol{padding-left:24px}
.prose ul{list-style:disc}
.prose li+li{margin-top:8px}
code{font-family:var(--font-mono);overflow-wrap:anywhere;font-size:.9em;background:var(--panel-2);border-radius:var(--r-focus);padding:.1em .3em}
pre{max-width:100%;overflow-x:auto;padding:24px;background:var(--panel-2);border:1px solid var(--border);border-radius:var(--r-card)}
pre code{padding:0;white-space:pre;overflow-wrap:normal}
.decorated,.stripe-halo{position:relative;overflow-x:clip;max-width:100%}
#server-status{position:relative;display:block;min-width:0;max-width:100%;overflow:hidden;margin-block:32px}
#server-status+*{margin-top:32px}
.reveal{transition:opacity var(--reveal-duration) var(--ease),transform var(--reveal-duration) var(--ease)}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:10px;min-height:52px;padding:12px 28px;
  border:0;border-radius:var(--r-pill);font-size:var(--size-body);font-weight:var(--weight-display);font-family:var(--font-body);
  text-decoration:none;white-space:nowrap;flex-shrink:0;max-width:100%;
  transition:background-color var(--duration) var(--ease),color var(--duration) var(--ease),box-shadow var(--duration) var(--ease);
}
.btn svg{width:16px;height:16px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
.btn-solid,.btn-primary{background:var(--accent);color:var(--white);box-shadow:inset 0 1px 0 var(--white-a22),0 10px 24px var(--accent-a25)}
.btn-solid:hover,.btn-primary:hover,.btn-solid.is-hover{background:var(--accent-dark)}
.btn-solid:active,.btn-primary:active{box-shadow:inset 0 2px 4px var(--accent-a25)}
.btn-line,.btn-secondary{color:var(--text);background:var(--clear);box-shadow:inset 0 0 0 1.5px var(--text)}
.btn-line:hover,.btn-secondary:hover{background:var(--panel)}
.btn-small{min-height:38px;padding:7px 18px;font-size:var(--size-small)}
.cta-row{display:flex;flex-wrap:wrap;gap:12px;margin-top:32px}
#site-header{min-height:var(--header-height);position:relative;z-index:300}
.topbar{height:var(--header-height);display:flex;align-items:center;flex-wrap:nowrap;gap:18px;padding:0 40px;position:relative;z-index:103;background:var(--clear)}
.brand{display:inline-flex;align-items:center;gap:10px;color:var(--text);text-decoration:none;flex:none;min-height:32px}
.brand img{width:28px;height:28px}
.brand-word{font-family:var(--font-display);font-size:19px;font-weight:var(--weight-strong);letter-spacing:var(--tracking-cjk)}
.mainnav{flex:1;display:flex;justify-content:center;min-width:0}
.mainnav ul{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:2px}
.mainnav a{display:inline-flex;align-items:center;gap:6px;min-height:36px;padding:6px 6px;border-radius:var(--r-pill);font-size:var(--size-small);color:var(--muted);text-decoration:none;white-space:nowrap;transition:background-color var(--duration),color var(--duration)}
.mainnav a svg,.drawer a svg{width:16px;height:16px;fill:none;stroke:currentColor;stroke-width:1.6;stroke-linecap:round;stroke-linejoin:round}
.mainnav a:hover{background:var(--ink-a06);color:var(--text)}
.mainnav a[aria-current="page"]{color:var(--text);background:var(--panel);box-shadow:inset 0 0 0 1px var(--border),0 2px 8px var(--accent-a06)}
.top-actions{display:flex;align-items:center;gap:10px;flex-shrink:0}
.lang-wrap{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:38px;min-width:44px;width:auto;padding:0 12px;border:0;border-radius:var(--r-pill);background:var(--clear);font-family:var(--font-body);font-size:var(--size-small);color:var(--muted)}
.lang svg{width:16px;height:16px;fill:none;stroke:currentColor;stroke-width:1.5}
.lang-text{white-space:nowrap}
.lang-caret{font-size:11px}
.lang:hover{color:var(--text);background:var(--ink-a06)}
.lang-panel{position:absolute;top:calc(100% + 10px);right:0;z-index:110;min-width:180px;padding:8px;background:var(--panel);border:1px solid var(--border);border-radius:var(--r-lg);box-shadow:var(--shadow-card)}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;color:var(--text);text-decoration:none;border-radius:var(--r-focus)}
.lang-panel a:hover,.lang-panel a[aria-current]{background:var(--panel-2)}
.login{display:inline-flex;align-items:center;justify-content:center;gap:7px;min-height:38px;padding:8px 18px 8px 15px;border-radius:var(--r-pill);background:var(--text);color:var(--panel);font-size:var(--size-small);font-weight:var(--weight-display);text-decoration:none;white-space:nowrap;box-shadow:inset 0 1px 0 var(--white-a22)}
.login svg{width:16px;height:16px;fill:none;stroke:currentColor;stroke-width:1.6;stroke-linecap:round}
.login:hover{background:var(--accent-dark)}
.menu-toggle{display:none;align-items:center;justify-content:center;min-width:44px;min-height:44px;border:1px solid var(--border);border-radius:var(--r-pill);background:var(--panel);color:var(--text)}
.menu-toggle svg{display:block;width:20px;height:20px;fill:none;stroke:currentColor;stroke-width:2;stroke-linecap:round}
.drawer{position:fixed;top:var(--header-height);inset-inline:0;z-index:102;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;padding:16px var(--gutter) 32px;background:var(--panel);border-top:1px solid var(--border)}
.drawer a{display:flex;align-items:center;gap:12px;width:100%;min-height:44px;padding:8px 16px;color:var(--text);text-decoration:none;border-radius:var(--r-focus)}
.drawer a:hover,.drawer a[aria-current]{background:var(--panel-2)}
.drawer-languages{border-top:1px solid var(--border);margin-top:16px;padding-top:16px}
html.nav-open .topbar{position:fixed;inset:0 0 auto;background:var(--panel);z-index:1002}
html.nav-open .drawer{z-index:1001}
html.nav-open .nav-veil{pointer-events:none}
@media(max-width:768px){.drawer{padding:8px 16px}.drawer a{min-height:44px;padding:8px 16px;font-size:14px}.drawer-languages{margin-top:8px;padding-top:8px}}
.nav-veil{position:fixed;top:var(--header-height);inset-inline:0;bottom:0;z-index:101;border:0;background:var(--veil)}
.site-footer{border-top:1px solid var(--border);background:var(--panel-2);padding-top:56px;padding-bottom:28px;margin-top:64px}
.footer-grid{display:grid;grid-template-columns:1.3fr 1fr 1fr;gap:48px}
.footer-grid>*{min-width:0}
.footer-brand p{margin-top:20px;max-width:30em;color:var(--muted)}
.footer-heading{font-size:var(--size-small);font-weight:var(--weight-strong);margin-bottom:16px}
.footer-links{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:6px 16px}
.footer-links a,.footer-languages a,.footer-legal a{display:inline-flex;align-items:center;min-height:28px;color:var(--text);text-decoration:none;font-size:var(--size-small)}
.footer-links a:hover,.footer-languages a:hover,.footer-legal a:hover{text-decoration:underline}
.footer-languages{display:flex;flex-wrap:wrap;gap:12px 24px;border-top:1px solid var(--border);padding-top:24px;margin-top:40px}
.footer-bottom{display:flex;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:16px;margin-top:24px;color:var(--muted);font-size:var(--size-small)}
.footer-legal{display:flex;flex-wrap:wrap;gap:24px}
@media(max-width:1240px){
  .topbar{padding:0 40px;gap:18px}.mainnav a{padding-inline:8px;font-size:13.5px}
}
@media(max-width:1120px){
  .mainnav{display:none}.menu-toggle{display:inline-flex}.top-actions{margin-left:auto}
}
@media(min-width:1121px){.drawer,.nav-veil{display:none!important}}
@media(max-width:768px){
  :root{--gutter:20px;--size-h1:36px;--size-h2:28px}
  .topbar{padding-inline:20px;gap:12px}.sec{padding-top:48px;padding-bottom:48px}
  .grid-three{grid-template-columns:minmax(0,1fr)}.grid-five{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-grid{grid-template-columns:minmax(0,1fr);gap:32px}
  .lang-text{display:none}
}
@media(max-width:640px){
  :root{--gutter:16px}
  .no-break{white-space:normal}.tilt{transform:none}
  .decorated,.stripe-halo{max-width:100%}
  .topbar{padding-inline:16px;gap:8px}.top-actions{gap:6px;margin-left:auto}
  .brand{gap:7px}.brand-word{font-size:17px}.brand img{width:25px;height:25px}
  .login{padding-inline:12px;min-height:38px}.login svg{display:none}
  .lang{padding-inline:8px}.lang-caret{display:none}
  .card,.panel{padding:22px}.grid-five{grid-template-columns:minmax(0,1fr)}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal,.reveal.pending{opacity:1;transform:none;transition:none}
  .btn,.login,.mainnav a{transition:none}
}